On novel elastic structures inducing polariton resonances with finite frequencies and cloaking due to anomalous localized resonances

This paper is concerned with the theoretical study of polariton resonances for linear elasticity governed by the Lamé system in R³, and their application for cloaking due to anomalous localized resonances. We derive a very general and novel class of elastic structures that can induce polariton resonances. It is shown that if either one of the two convexity conditions on the Lamé parameters is broken, then we can construct certain polariton structures that induce resonances. This significantly extends the relevant existing studies in the literature where the violation of both convexity conditions is required. Indeed, the existing polariton structures are a particular case of the general structures constructed in our study. Furthermore, we consider the polariton resonances within the finite frequency regime, and rigorously verify the quasi-static approximation for diametrically small polariton inclusions. Finally, as an application of the newly found structures, we construct a polariton device of the core-shell-matrix form that can induce cloaking due to anomalous localized resonance in the quasi-static regime, which also includes the existing study as a special case.